1. Field of the Invention
The present invention relates to golf ball covers and mantles comprising glass particles, preferably surface treated glass particles.
2. Description of the Related Art
Modern golf balls typically employ ionomeric resins or polyurethanes as cover materials. Ionomeric resins, as a result of their toughness, durability, and wide range of hardness values, have become materials of choice for golf ball covers over traditional rubbers. Ionomeric resins generally comprise an alpha-olefin and an alpha, beta-ethylenically unsaturated mono- or dicarboxylic acid neutralized with metal ions to the extent desired. Olefins which have been employed to prepare ionomeric resins include ethylene, propylene, butene-1 and the like. Unsaturated carboxylic acids which have been employed to prepare ionomeric resins include acrylic, methacrylic, ethacrylic, o-chloroacrylic, crotonic, maleic, fumaric, itaconic and the like. Ionomeric resins include copolymers of ethylene with acrylic acid such as those sold by Exxon Corporation under the trademark “IOTEK”, as well as copolymers of ethylene with methacrylic acid such as those sold by E.I. DuPont Nemours & Company under the trademark “SURLYN”. In some instances, a softening comonomer such as an acrylate ester has been included such that the ionomeric copolymer is an ionomeric terpolymer. Although various compositions have been employed to provide golf balls of varying playability characteristics, a need continues for compositions and covers which can be employed to provide golf balls that exhibit good playability and durability.
There are no commercially available golf balls that are generally known to contain surface treated glass particles or materials. The glass particles may be used in a golf ball cover or cover layers, in the mantle, or both, to reinforce the golf ball cover layer(s) and/or mantle layer. U.S. Pat. No. 6,193,617 discloses golf balls with an outer cover comprising hard particles such as diamond particles, and a predetermined number of the hard particles protrude from the outer surface of the outer cover. However, there is no indication in the patent that surface treated glass particles can be used in a golf ball cover or mantle layer.
In view of known strength and durability properties of glass and glass particles, it would be desirable to utilize glass particles in the construction of a golf ball. Specifically, it would be desirable to use surface treated glass particles in a golf ball cover and/or mantle layer. There is a particular need for improved golf ball cover and mantle materials, particularly golf balls with increased compression and coefficient of restitution as well as improved durability with the same or higher coefficient of restitution.